Emergence of complexity in hierarchically organized chiral particles.

Science (New York, N.Y.) (2020-04-11)
Wenfeng Jiang, Zhi-Bei Qu, Prashant Kumar, Drew Vecchio, Yuefei Wang, Yu Ma, Joong Hwan Bahng, Kalil Bernardino, Weverson R Gomes, Felippe M Colombari, Asdrubal Lozada-Blanco, Michael Veksler, Emanuele Marino, Alex Simon, Christopher Murray, Sérgio Ricardo Muniz, André F de Moura, Nicholas A Kotov
ABSTRACT

The structural complexity of composite biomaterials and biomineralized particles arises from the hierarchical ordering of inorganic building blocks over multiple scales. Although empirical observations of complex nanoassemblies are abundant, the physicochemical mechanisms leading to their geometrical complexity are still puzzling, especially for nonuniformly sized components. We report the self-assembly of hierarchically organized particles (HOPs) from polydisperse gold thiolate nanoplatelets with cysteine surface ligands. Graph theory methods indicate that these HOPs, which feature twisted spikes and other morphologies, display higher complexity than their biological counterparts. Their intricate organization emerges from competing chirality-dependent assembly restrictions that render assembly pathways primarily dependent on nanoparticle symmetry rather than size. These findings and HOP phase diagrams open a pathway to a large family of colloids with complex architectures and unusual chiroptical and chemical properties.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
L-Cysteine hydrochloride monohydrate, reagent grade, ≥98% (TLC)
Sigma-Aldrich
L-Penicillamine, 99%
Sigma-Aldrich
DL-Cysteine, technical grade
Sigma-Aldrich
Copper(II) chloride dihydrate, ≥99.95% trace metals basis
Sigma-Aldrich
D-Cysteine hydrochloride monohydrate, ≥98% (TLC)
Sigma-Aldrich
DL-Cysteine hydrochloride, ≥95% (TLC), anhydrous